Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	$ 444	$ 507
Income tax expense	57	71
Other expense	45	79
Amounts reclassified from AOCI	(198)	(236)
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	1	1
Reclassification out of Accumulated Other Comprehensive Income | Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	(1)	(2)
Income tax expense	0	1
Amounts reclassified from AOCI	(1)	(1)
Reclassification out of Accumulated Other Comprehensive Income | Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense	0	(2)
Other expense	2	4
Amounts reclassified from AOCI	$ 2	$ 2